The present invention relates to a bill recognizing apparatus for recognizing and processing the sample data read from bills.
In the prior art bill(paper money) recognizing system, a main sensor section in a bill recognizing apparatus performs data sampling of a bill in synchronism with an encoder pulse. In the data sampling, a skew detection is made when the bill has been fed as long as 24 mm from the edge into the image sensor section.
Depending on the skew condition, the address is determined to transfer the data sampled by the image sensor section for initiating DMA (direct memory access) operation in synchronism with the encoder pulse. In other words, the DMA operation corrects the skew of the data sampled by the image sensor section.
When completing transfer of all sampled data by the DMA operation, a CPU (microprocessor) software performs the following: the read-out processing of the sampled data from the transferred address (read-out processing of the skew corrected data); the compression processing for extracting the features in the data; and the reference processing with the compressed data and the dictionary data of various bills (28 kinds of dictionary data). As a result, the kind of bill in the dictionary data closest to the sampled data is determined.
The feed time of the 24 mm required for skew correction and the time required for complicated and repeated software processing results in delay for recognizing the correct kind of bill. Also, a longer distance is required for the mechanism to switch the transportation path depending on the recognition of the bill. As a result, it was difficult to miniaturize a bill recognizing apparatus.
In the conventional bill recognizing system, a common counter is used for generating an address for temporary storage of the sampled data and an address for DMA operation for skew correction. Accordingly, the DMA operation is performed in response to the encoder pulse which is a timing pulse for sampling the data of every 1 mm of the bill at its feed rate.
The time required for recognizing the skew condition and correcting the skew at the 24 mm position of the bill from the front edge affects until all sampled data is transferred and the DMA operation is completed. This causes a path to transport the bill during the above mentioned time.
For example, in the case of a 1500 mm/s feed rate, the time required for determining the skew correction factor is 16 ms, an additional 60 ms is required for software processing is 60 ms. As a result, the feed path for the bill for a total 76 ms is long as about 2,114 mm.